Sam,
You can use HTML tags only when you're logged-in as a Registered User (see http://www.8052.com).
Anyway, here's your diagram with the monospaced font:

 
     C C C 
     1 2 3 
     | | | 
     v v v 
R1<- 1 2 3 <-pullup 
R2<- 4 5 6 <-pullup 
R3<- 7 8 9 <-pullup 
R4<- * 0 # <-pullup 

BTW: some keypads have fairly high contact resistance (kOhms), so might not be suitable to drive LEDs directly.